The invention relates to buckles of a kind suitable for use in a vehicle seat belt system.
Such buckles conventionally comprise a tongue part and a socket part, the tongue part having a tongue with a latch formation, and the socket part having a socket within which the tongue can be releasably latched by a latch mechanism having a latch member engageable with the latch formation.
Buckles of this kind require the tongue, on insertion into the socket, to engage the latch member to move this out of the path of the tongue to a position from which the latch member returns under spring pressure to latch the tongue in place; the tongue consequently experiences considerable resistance to insertion, and undesirable lateral loading. In some instances therefore the latch members engage the tongue so as to oppose withdrawal with only limited strength. The latch members can in some instances be displayed to release the tongue by inertial forces experienced when the buckle undergoes a sharp deceleration, as during an accident.
It is accordingly an object of the invention to provide a tongue and socket buckle with a latching member which is held in the latching position thereof by a manually releasable catch element. It is a further object of the invention to provide a tongue and socket buckle with a latching member adapted to function also as an ejector member.
It is another object of the invention to provide a tongue and socket buckle in which a catch element is arranged to positively maintain a latch member in the latching position and to resist movement of the latch member to the latching position due to insertion of the tongue into the socket.
It is also an object of the invention to provide a tongue and socket buckle in which the socket latch member is retained in a non-latching position when the tongue is absent from the socket.
It is also an object of the invention to provide a tongue and socket buckle in which insertion of the tongue into the socket is resisted only by the force of an ejector spring for facilitating removal of the tongue on release of the buckle.
It is a further object of the invention to provide a tongue and socket buckle in which the energy needed to move the latch member to the locking position on insertion of the tongue is obtained from the previous release of the tongue from the socket.